Comparative Acute and Chronic Sensitivity of Fish and Amphibians: A Critical Review of Data

Abstract

Abstract-The relative sensitivity of amphibians to chemicals in the environment, including plant protection product active substances, is the subject of ongoing scientific debate. The objective of this study was to compare systematically the relative sensitivity of amphibians and fish to chemicals. Acute and chronic toxicity data were obtained from the U.S. Environmental Protection Agency (U.S. EPA) ECOTOX database and were supplemented with data from the scientific and regulatory literature. The overall outcome is that fish and amphibian toxicity data are highly correlated and that fish are more sensitive (both acute and chronic) than amphibians. In terms of acute sensitivity, amphibians were between 10-and 100-fold more sensitive than fish for only four of 55 chemicals and more than 100-fold more sensitive for only two chemicals. However, a detailed inspection of these cases showed a similar acute sensitivity of fish and amphibians. Chronic toxicity data for fish were available for 52 chemicals. Amphibians were between 10-and 100-fold more sensitive than fish for only two substances (carbaryl and dexamethasone) and greater than 100-fold more sensitive for only a single chemical (sodium perchlorate). The comparison for carbaryl was subsequently determined to be unreliable and that for sodium perchlorate is a potential artifact of the exposure medium. Only a substance such as dexamethasone, which interferes with a specific aspect of amphibian metamorphosis, might not be detected using fish tests. However, several other compounds known to influence amphibian metamorphosis were included in the analysis, and these did not affect amphibians disproportionately. These analyses suggest that additional amphibian testing is not necessary during chemical risk assessment. Environ. Toxicol. Chem. 2013;32:984-994.

Risks to Aquatic Organisms from Use of Chlorpyrifos in the United States

“…Just as there were strengths in the ERA there were several areas of uncertainty, some more relevant than others. There were few usable toxicity data from amphibians, but evaluations of the relative sensitivity of fi sh and amphibians to several classes of toxicants (Weltje et al 2013 ) suggest that toxicity data from fi sh can provide equivalency for amphibians. There were few data on recovery of AChE, the target enzyme for CPY, in aquatic organisms, and this is an uncertainty in the analysis of the relevance of the duration between exposure-events.…”

“…Because of the paucity of data, an SSD was not constructed. Larval stages of amphibians have been observed to be less sensitive than fi sh to a range of chemicals (Weltje et al 2013 ), and the toxicity data for fi sh can be extrapolated to and be protective of amphibians. Therefore, aquatic stages of amphibians were not considered further in the ERA.…”

Guidance on tiered risk assessment for plant protection products for aquatic organisms in edge‐of‐field surface waters

“…The assessment is only valid for acute toxicity (mortality) and will not necessarily be predictive of chronic toxicity. However, a recent study indicates that the same is also applicable for chronic toxicity (Weltje et al, 2013).…”

Exposure to rodenticides in Northern Spotted and Barred Owls on remote forest lands in northwestern California: evidence of food web contamination

“…Although BO are also predominantly consumers of mammal species (60-70% rodents and lagomorphs), their diets include a higher portion of birds and insects as well as amphibians, fish, reptiles, snails, and crayfish. Previous studies have detected AR in insects, reptiles, fish, and mollusk species, but many of these accounts stem from experimental toxicity studies or were part of monitoring efforts after accidental AR discharge or intensive AR application for eradication of invasive species (Eason and Spurr 1995, Primus et al 2005, Rueda et al 2005, Weltje et al 2013, Weir et al 2015.…”